MCANet: An Unsupervised Multi-Constraint Cascaded Attention Network for Accurate and Smooth Brain Medical Image Registration

Brain medical image registration is a fundamental premise for the computer-assisted treatment of brain diseases. The brain is one of the most important and complex organs of the human body, and it is very challenging to perform accurate and fast registration on it. Aiming at the problem of voxel folding in the deformation field and low registration accuracy when facing complex and fine objects, this paper proposed a fully convolutional multi-constraint cascaded attention network (MCANet). The network is composed of two registration sub-network cascades and performs coarse-to-fine registration of input image pairs in an iterative manner. The registration subnetwork is called the dilated self-attention network (DSNet), which incorporates dilated convolution combinations with different dilation rates and attention gate modules. During the training of MCANet, a double regularization constraint was applied to punish, in a targeted manner, the excessive deformation problem, so that the network can generate relatively smooth deformation while having high registration accuracy. Experimental results on the Mindboggle101 dataset showed that the registration accuracy of MCANet was significantly better than several existing advanced registration methods, and the network can complete relatively smooth registration.